London, Jan 22: Its better to stay awake to increase the learning potential than long for more sleep as it is found that dozing off can have an adverse impact on brain's activities.
Researchers at the University of Wisconsin School of Medicine and Public Health has come to the conclusion that sleep plays a critical role in the brain's ability to change in response to its environment. This ability, called ''plasticity'', is directly associated with learning, Science Daily reported. The UW-Madison scientists showed by several measures that synapses, nerve cell connections central to brain plasticity, were very strong when rodents had been awake and weak when they had been asleep.
The theory is in contradiction with the popular belief that people sleep so that their synapses can relax and prepare for a new day and the next round of learning and synaptic strengthening.
Associate professor of psychiatry and study author Chiara Cirelli explains that the human brain spends up to 80 per cent of its energy on synaptic activity, constantly adding and strengthening connections in response to all kinds of stimulation.
Given that each of the millions of neurons in the human brain contains thousands of synapses, this energy expenditure ''is huge and can't be sustained.'' ''We need an off-line period, when we are not exposed to the environment, to take synapses down,'' Ms Cirelli say.
''We believe that's why humans and all living organisms sleep.
Without sleep, the brain reaches a saturation point that taxes its energy budget, its store of supplies and its ability to learn further.'' To test the theory, researchers conducted both molecular and electro-physiological studies in rats to evaluate synaptic potentiation, or strengthening, and depression, or weakening, following sleeping and waking times.
The studies showed that rats had an almost 50 per cent receptor increase after a period of wakefulness compared to rats that had been asleep.
''We believe that learning occurs only when we are awake, and sleep's main function is to keep our brains and all its synapses lean and efficient,'' the researchers pointed out.